Drug · FAERS side-effect profile with label screen
Chlorpheniramine side effects: what 6,549 FDA adverse event reports show
Drug class
Not stated in label
Label matched
Chlorpheniramine Maleate (Aller-Chlor)
closest FDA label found for this product string; brand list suppressed because the label is a related product, not an exact match
Who reports
6,549 reports · 86% serious · 1,131 with death outcome · 60% female
openFDA FAERS counts, all years, deduplication not applied
Used for
temporarily relieves these symptoms due to hay fever or other upper respiratory allergies: sneezing runny nose itchy, watery eyes itching of the nose or throat
FDA label, Indications and Usage
Boxed warning
None in the current label
How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation.
Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)?
That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.
Causality screen of the 40 strongest signals
Reporting / coding artifact 3Lab value / disease marker 6No label text to screen 31
What the badges mean
- Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
- Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
- Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
- No label text to screen No validated FDA label was retrievable for this product, so the screen could not run. Disproportionality only.
Strongest disproportionality signals
Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 550 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
Show:
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Neutrophil count increased | 66 | 20.7 16.3–26.3ROR 20.9 · χ² 1,209 / p 4e-265 | 20.4 EB05 16.6 · IC025 +3.8 3/3 methods agree | Lab value / disease marker | serious PRR 15.2 · ♀ 7% (drug 60%) | no trial data cached |
| Mucosal inflammation | 148 | 18.3 15.6–21.4ROR 18.7 · χ² 2,388 / p <1e-300 | 18.1 EB05 15.8 · IC025 +3.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 12.9 · 92% clinician | no trial data cached |
| Appendicitis | 51 | 17.6 13.4–23.2ROR 17.8 · χ² 780 / p 5e-172 | 17.4 EB05 13.7 · IC025 +3.5 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 11.7 · ♀ 40% (drug 60%) · 98% clinician | no trial data cached |
| Schizophrenia | 63 | 16.7 13.0–21.3ROR 16.8 · χ² 907 / p 1e-199 | 16.5 EB05 13.3 · IC025 +3.5 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 11.5 · ♀ 0% (drug 60%) | no trial data cached |
| Toxic epidermal necrolysis (severe skin peeling reaction) | 70 | 14.9 11.8–18.8ROR 15.1 · χ² 892 / p 3e-196 | 14.8 EB05 12.0 · IC025 +3.4 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 10.0 · ♀ 35% (drug 60%) · 95% clinician | no trial data cached |
| Ejection fraction decreased | 72 | 14.9 11.8–18.7ROR 15.0 · χ² 914 / p 6e-201 | 14.7 EB05 12.0 · IC025 +3.4 3/3 methods agree | Lab value / disease marker | serious PRR 10.8 · ♀ 97% (drug 60%) · 100% clinician | no trial data cached |
| Lymphocyte count decreased | 73 | 13.3 10.5–16.7ROR 13.4 · χ² 813 / p 5e-179 | 13.1 EB05 10.7 · IC025 +3.2 3/3 methods agree | Lab value / disease marker | serious PRR 10.7 · ♀ 6% (drug 60%) · 90% clinician | no trial data cached |
| Hallucination, auditory | 64 | 12.9 10.1–16.5ROR 13.0 · χ² 689 / p 3e-152 | 12.7 EB05 10.2 · IC025 +3.1 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 10.0 · ♀ 5% (drug 60%) | no trial data cached |
| Sars-cov-2 test positive | 53 | 12.7 9.7–16.7ROR 12.8 · χ² 560 / p 4e-124 | 12.5 EB05 9.8 · IC025 +3.1 3/3 methods agree | Lab value / disease marker | serious n=50 · ♀ 7% (drug 60%) · 94% clinician | no trial data cached |
| Ventricular fibrillation | 42 | 12.1 9.0–16.4ROR 12.2 · χ² 416 / p 1e-92 | 11.7 EB05 8.9 · IC025 +2.9 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 8.1 · ♀ 28% (drug 60%) · 100% clinician | no trial data cached |
| Cytokine release syndrome | 67 | 11.3 8.9–14.3ROR 11.4 · χ² 616 / p 2e-136 | 11.0 EB05 8.9 · IC025 +3.0 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.5 · 96% clinician | no trial data cached |
| Febrile neutropenia | 231 | 11.2 9.9–12.7ROR 11.6 · χ² 2,135 / p <1e-300 | 11.1 EB05 9.9 · IC025 +3.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.5 · ♀ 38% (drug 60%) · 97% clinician | no trial data cached |
| Lower respiratory tract infection | 155 | 11.0 9.4–12.8ROR 11.2 · χ² 1,394 / p <1e-300 | 10.8 EB05 9.5 · IC025 +3.1 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.7 · 91% clinician | no trial data cached |
| Sinus tachycardia | 45 | 10.2 7.6–13.6ROR 10.3 · χ² 363 / p 3e-81 | 9.7 EB05 7.4 · IC025 +2.7 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.0 · 93% clinician | no trial data cached |
| Neuropathy peripheral (nerve damage in hands/feet) | 275 | 9.3 8.3–10.5ROR 9.7 · χ² 2,041 / p <1e-300 | 9.2 EB05 8.3 · IC025 +3.0 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.2 | no trial data cached |
| Extrapyramidal disorder | 72 | 9.2 7.3–11.6ROR 9.3 · χ² 518 / p 6e-115 | 8.9 EB05 7.2 · IC025 +2.7 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.9 · ♀ 5% (drug 60%) | no trial data cached |
| Cardiogenic shock | 40 | 9.0 6.6–12.3ROR 9.0 · χ² 276 / p 3e-62 | 8.4 EB05 6.4 · IC025 +2.5 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.0 · ♀ 14% (drug 60%) · 100% clinician | no trial data cached |
| Hyperlipidaemia | 30 | 8.0 5.6–11.5ROR 8.1 · χ² 177 / p 1e-40 | 7.3 EB05 5.3 · IC025 +2.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 5.5 · ♀ 37% (drug 60%) · 93% clinician | no trial data cached |
| Neutrophil count decreased | 100 | 7.9 6.5–9.6ROR 8.0 · χ² 597 / p 4e-132 | 7.7 EB05 6.5 · IC025 +2.6 3/3 methods agree | Lab value / disease marker | serious PRR 6.0 · 91% clinician | no trial data cached |
| Ascites | 71 | 7.7 6.1–9.8ROR 7.8 · χ² 410 / p 2e-91 | 7.4 EB05 6.1 · IC025 +2.5 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 5.3 · 96% clinician | no trial data cached |
| Infusion related reaction (reaction during infusion) | 157 | 7.6 6.5–8.9ROR 7.8 · χ² 897 / p 2e-197 | 7.5 EB05 6.5 · IC025 +2.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.0 · 90% clinician | no trial data cached |
| Bacterial infection | 44 | 7.6 5.7–10.2ROR 7.6 · χ² 245 / p 1e-55 | 7.1 EB05 5.5 · IC025 +2.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 5.8 · ♀ 30% (drug 60%) · 93% clinician | no trial data cached |
| Blood test abnormal | 33 | 7.5 5.4–10.6ROR 7.6 · χ² 180 / p 2e-41 | 6.9 EB05 5.1 · IC025 +2.2 3/3 methods agree | Reporting / coding artifact | serious PRR 7.7 · 97% clinician | no trial data cached |
| Seasonal allergy | 33 | 7.5 5.3–10.5ROR 7.5 · χ² 179 / p 4e-41 | 6.9 EB05 5.1 · IC025 +2.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious n=18 · 79% consumer | no trial data cached |
| Neuralgia | 56 | 7.4 5.7–9.6ROR 7.5 · χ² 303 / p 3e-68 | 7.0 EB05 5.6 · IC025 +2.4 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.4 · 96% clinician | no trial data cached |
| Hypokalaemia (low potassium) | 105 | 7.3 6.1–8.9ROR 7.4 · χ² 568 / p 7e-126 | 7.1 EB05 6.0 · IC025 +2.5 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.9 · 93% clinician | no trial data cached |
| Psychotic disorder | 66 | 7.2 5.6–9.1ROR 7.2 · χ² 344 / p 5e-77 | 6.9 EB05 5.6 · IC025 +2.4 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 5.2 · ♀ 0% (drug 60%) | no trial data cached |
| Incorrect route of product administration | 37 | 7.1 5.1–9.7ROR 7.1 · χ² 186 / p 1e-42 | 6.6 EB05 4.9 · IC025 +2.2 3/3 methods agree | Reporting / coding artifact | serious PRR 8.9 · ♀ 25% (drug 60%) · 95% clinician | no trial data cached |
| Neutropenia (low neutrophils (infection-fighting cells)) | 295 | 7.0 6.2–7.8ROR 7.3 · χ² 1,512 / p <1e-300 | 6.9 EB05 6.3 · IC025 +2.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.8 · 94% clinician | no trial data cached |
| Hyponatraemia (low sodium) | 121 | 6.9 5.8–8.2ROR 7.0 · χ² 605 / p 6e-134 | 6.7 EB05 5.8 · IC025 +2.4 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.7 · 97% clinician | no trial data cached |
| Cellulitis (skin infection) | 107 | 6.8 5.6–8.2ROR 6.9 · χ² 524 / p 3e-116 | 6.6 EB05 5.6 · IC025 +2.4 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 5.0 · ♀ 17% (drug 60%) | no trial data cached |
| Hypomagnesaemia | 29 | 6.7 4.7–9.6ROR 6.7 · χ² 135 / p 2e-31 | 6.1 EB05 4.4 · IC025 +2.0 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.6 · ♀ 23% (drug 60%) | no trial data cached |
| Blood bilirubin increased | 53 | 6.3 4.8–8.2ROR 6.3 · χ² 229 / p 4e-52 | 6.0 EB05 4.7 · IC025 +2.1 3/3 methods agree | Lab value / disease marker | serious PRR 4.7 | no trial data cached |
| Lip swelling | 65 | 6.3 4.9–8.0ROR 6.3 · χ² 283 / p 1e-63 | 6.0 EB05 4.9 · IC025 +2.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.5 | no trial data cached |
| Dermatitis contact | 22 | 6.2 4.1–9.4ROR 6.2 · χ² 91 / p 8e-22 | 5.5 EB05 3.8 · IC025 +1.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious n=18 | no trial data cached |
| Bronchospasm (airway tightening) | 27 | 6.0 4.1–8.8ROR 6.1 · χ² 109 / p 1e-25 | 5.5 EB05 4.0 · IC025 +1.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.3 · 96% clinician | no trial data cached |
| Covid-19 pneumonia | 22 | 5.9 3.9–9.0ROR 5.9 · χ² 85 / p 1e-20 | 5.3 EB05 3.7 · IC025 +1.7 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 3.9 · 100% clinician | no trial data cached |
| Retinal detachment | 17 | 5.9 3.7–9.5ROR 5.9 · χ² 65 / p 4e-16 | 5.2 EB05 3.4 · IC025 +1.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.0 | no trial data cached |
| Disease progression | 215 | 5.8 5.1–6.7ROR 6.0 · χ² 862 / p 1e-189 | 5.8 EB05 5.1 · IC025 +2.3 3/3 methods agree | Reporting / coding artifact | serious PRR 4.5 · 92% clinician | no trial data cached |
| Neoplasm progression | 64 | 5.8 4.6–7.5ROR 5.9 · χ² 252 / p 5e-57 | 5.6 EB05 4.5 · IC025 +2.1 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 5.3 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).
Most frequently reported reactions
By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Nausea | 635 | 2.6 2.4–2.8ROR 2.7 · χ² 635 / p 2e-140 | 2.6 EB05 2.4 · IC025 +1.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 2.9 | no trial data cached |
| Diarrhoea (diarrhea) | 583 | 2.9 2.7–3.1ROR 3.1 · χ² 747 / p 7e-165 | 2.9 EB05 2.7 · IC025 +1.4 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 3.0 | no trial data cached |
| Off label use (used outside approved label) | 533 | 2.0 1.8–2.1ROR 2.1 · χ² 263 / p 2e-59 | 2.0 EB05 1.8 · IC025 +0.8 | Reporting / coding artifact | serious PRR 2.4 | no trial data cached |
| Fatigue (tiredness) | 514 | 2.1 1.9–2.3ROR 2.2 · χ² 314 / p 2e-70 | 2.1 EB05 2.0 · IC025 +0.9 | No label text to screen label has no adverse-reaction text | serious PRR 2.3 | no trial data cached |
| Dyspnoea (shortness of breath) | 455 | 2.6 2.4–2.8ROR 2.7 · χ² 449 / p 6e-100 | 2.6 EB05 2.4 · IC025 +1.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 2.2 | no trial data cached |
| Pyrexia (fever) | 411 | 3.8 3.5–4.2ROR 4.0 · χ² 859 / p 3e-189 | 3.8 EB05 3.5 · IC025 +1.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 3.1 | no trial data cached |
| Vomiting | 403 | 2.8 2.5–3.0ROR 2.9 · χ² 458 / p 7e-102 | 2.7 EB05 2.5 · IC025 +1.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 2.5 | no trial data cached |
| Pneumonia (lung infection) | 297 | 2.9 2.6–3.3ROR 3.0 · χ² 384 / p 7e-86 | 2.9 EB05 2.7 · IC025 +1.4 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 2.1 | no trial data cached |
| Neutropenia (low neutrophils (infection-fighting cells)) | 295 | 7.0 6.2–7.8ROR 7.3 · χ² 1,512 / p <1e-300 | 6.9 EB05 6.3 · IC025 +2.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.8 · 94% clinician | no trial data cached |
| Headache | 292 | 1.5 1.3–1.7ROR 1.5 · χ² 48 / p 2e-12 | 1.5 EB05 1.4 · IC025 +0.4 | No label text to screen label has no adverse-reaction text | serious PRR 1.6 · ♀ 81% (drug 60%) | no trial data cached |
| Neuropathy peripheral (nerve damage in hands/feet) | 275 | 9.3 8.3–10.5ROR 9.7 · χ² 2,041 / p <1e-300 | 9.2 EB05 8.3 · IC025 +3.0 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.2 | no trial data cached |
| Rash | 271 | 2.0 1.8–2.2ROR 2.0 · χ² 137 / p 5e-32 | 2.0 EB05 1.8 · IC025 +0.8 | No label text to screen label has no adverse-reaction text | serious PRR 2.6 | no trial data cached |
| Cough | 268 | 3.1 2.7–3.4ROR 3.2 · χ² 376 / p 5e-84 | 3.1 EB05 2.8 · IC025 +1.4 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 3.0 | no trial data cached |
| Pruritus (itching) | 265 | 2.2 2.0–2.5ROR 2.3 · χ² 185 / p 2e-42 | 2.2 EB05 2.0 · IC025 +1.0 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 3.1 | no trial data cached |
| Constipation | 264 | 3.9 3.5–4.4ROR 4.0 · χ² 574 / p 5e-127 | 3.9 EB05 3.5 · IC025 +1.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.2 | no trial data cached |
Unlabeled candidate signals
Every screened signal with n ≥ 20 was either labeled, an indication term, or an artifact pattern — no unlabeled candidate stood out in the top signals.
Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.
Common questions
What are the most reported side effects of Chlorpheniramine?
In FDA FAERS, the most frequently co-reported reaction terms for Chlorpheniramine are nausea, diarrhoea, fatigue, dyspnoea, pyrexia, vomiting. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.
Does Chlorpheniramine have an FDA boxed warning?
No. The FDA label retrieved for Chlorpheniramine has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Chlorpheniramine causes these side effects?
No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.
Sources & methods
- FDA label via openFDA (set ID 04ca3806-72be-47d4-9fea-5b0dee087683, effective 20260708; matched on
openfda.generic_name.exact:"CHLORPHENIRAMINE MALEATE") - Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
- FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA
count=aggregation, fieldpatient.drug.openfda.generic_name.exact, 590 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction - Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
- Seriousness and sex counts from openFDA
count=serious,patient.patientsex,seriousnessdeath
Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.